On 23 May 2011, Callejón re-joined Real Madrid on a five-year deal effective as of 1 July, for a reported fee of €5.5 million.[13] On 16 July, he played his first match for them in a 4–1 friendly win over the Los Angeles Galaxy, scoring the first goal of the game in the 30th minute.[14]

On 2 October 2011, Callejón netted his first official goal for Real Madrid after coming on midway through the second half of an away fixture against former club Espanyol; he scored from a Cristiano Ronaldoassist in an eventual 4–0 win but did not celebrate the goal, instead raising his arms in the air in a mark of respect for his former employer.[15]

As a starter, Callejón continued with his impressive scoring form: he scored once in a 6–2 away win over Sevilla on 17 December 2011,[18] and in the tie against SD Ponferradina for the season's Copa del Rey he netted three of his team's seven aggregate goals, scoring one away and two at home.[19][20]

On 14 January 2012, Callejón scored the winner in a 2–1 success at Mallorca, helping the visitors come from behind with his 84th-minute long-range strike.[21] In the following matchday he added another, closing the score in a 4–1 home win over Athletic Bilbao.[22]

Callejón netted his first goal of 2014–15 on the opening day of the Serie A campaign, the opener in a 2–1 win over Genoa CFC.[30] His second came on 24 September, as he scored at the stroke of half-time to put Napoli up 3–2 against U.S. Città di Palermo in an eventual 3–3 home draw.[31] On 19 October, he scored twice in a 2–2 draw at Internazionale, with all four of the game's goals coming in the match's last 11 minutes.[32]

In the Derby del Sole match against A.S. Roma on 2 November, Callejón hit the post and had a shot saved off the line before eventually finding the net late on in Napoli's 2–0 victory.[33] The strike took his league goal tally to eight on the season, two more than his closest competitors, and he was included in the Serie A Team of the Week lineup.[34]

A versatile, tenacious and hard-working right-footed player, Callejón is capable of playing anywhere along the front line, and has been used as a forward, as a winger on either flank, in the centre as an attacking midfielder and as a supporting striker. Although he usually occupies a position in or behind the main attacking line, due to his personality and ability to provide balance to his teams by linking-up play between the forwards and midfielders, he is also capable of playing in the centre as a main striker, and was also occasionally deployed in deeper roles under Mourinho during his time at Real Madrid, as a central midfielder or even as an attacking full-back or wingback.

A quick, mobile and creative player, with good technical ability, Callejón is capable of both creating and scoring goals, due to his powerful shot and excellent offensive movement off the ball, as demonstrated by his ability to lose his markers by make attacking runs in behind the defensive line and into the area from deeper or wider areas. He is also a good header of the ball, in spite of his average stature.[41][42][43][44][45][46]